On Tuesday 04 May 2010, Mark Brown wrote: > On Tue, May 04, 2010 at 11:06:39AM -0700, Kevin Hilman wrote: > > > With opportunistic suspend, all of this flexibility is gone, and the > > device/subsystem is told to go into the lowest power, highest latency > > state, period. > > Well, half the problem I have is that unfortunately it's not a case of > doing that period. The prime example I'm familiar with is that for > understandable reasons users become irate when you power down the audio > CODEC while they're in the middle of a call so if opportunistic PM is in > use then the audio subsystem needs some additional help interpreting a > suspend request so that it can figure out how to handle it. Similar > issues apply to PMICs, though less pressingly for various reasons. > > Just to be clear, I do understand and mostly agree with the idea that > opportunistic suspend presents a reasonable workaround for our current > inability to deliver good power savings with runtime PM methods on many > important platforms but I do think that if we're going to make this > standard Linux PM functionality then we need to be clearer about how > everything is intended to hang together. At the moment the rule of thumb is: if you don't need the opportunistic suspend, don't use it. It is not going to be enabled by default on anything other than Android right now. However, since Android is a legitimate user of the Linux kernel, I see no reason to reject this feature right away. There are many kernel features that aren't used by all platforms. Rafael _______________________________________________ linux-pm mailing list linux-pm@xxxxxxxxxxxxxxxxxxxxxxxxxx https://lists.linux-foundation.org/mailman/listinfo/linux-pm
